Breast and prostate cancers are two of the three diseases recently designated as high priority targets of the SPORE funding mechanisms. This conference includes researchers from each of these designated SPORE centers; along with many other current investigators, to promote maximal interaction and exchange. This is a unique meeting dedicated to a comparative, multidisciplinary approach in uncovering mechanisms at work in two of the deadliest cancers of men and women. Cancers of the mammary and prostate glands are uniquely linked in their dependence upon sex steroid hormones for onset and malignant progression. Recent studies have also begun to explore potential commonalities in mechanisms of familial pre-disposition, mutations of respective sex steroid receptors, oncogenes, and suppressor genes, mechanisms of local control by growth factors and mechanisms of metastatic spread to distant sites. The meeting will highlight dialogue in these areas with a goal of improved diagnosis and movement toward new chemo-,hormonal and biological therapies of the two diseases. Sessions will be designed to cross fertilize ideas in topics ranging from basic cell and molecular biology to new clinical trials based on new understanding of breast and prostate tumor biology and utilization of new therapeutic agents.